[Isolates] Merge from bleeding_edge to isolates, revisions 6100-6300.

test/mjsunit/regress/regress-900.js

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 26 matching lines @@
 // Make sure we can't overwrite an accessor, but that the setter is
 // instead called.
 b[1] = 'foobar';
 assertEquals(b[1], 'bar');
 assertEquals(b.x, 42);
 
 var desc = Object.getOwnPropertyDescriptor(b, "1");
 assertEquals(desc['writable'], undefined);
 assertFalse(desc['enumerable']);
 assertFalse(desc['configurable']);